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Article

Children’s Allergic Sensitization to Pets: The Role of Air Pollution

by
Yufeng Miao
1,†,
Yingjie Liu
1,†,
Ruixue Huang
2,
Yuan Xue
3,
Le Liu
3,* and
Qihong Deng
3,*
1
School of Energy Science and Engineering, Central South University, Changsha 410083, China
2
Xiangya School of Public Health, Central South University, Changsha 410078, China
3
School of Public Health, Zhengzhou University, Zhengzhou 450001, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Atmosphere 2025, 16(7), 833; https://doi.org/10.3390/atmos16070833
Submission received: 21 May 2025 / Revised: 28 June 2025 / Accepted: 30 June 2025 / Published: 9 July 2025
(This article belongs to the Special Issue Indoor Air Pollution: A Silent Threat to Human Health and the Atmosphere)
Browse Figure
Versions Notes

Abstract

Allergic sensitization (AS) to pets is a notable health concern, with a 10–30% prevalence in developed countries, significantly higher than in developing nations; however, the critical exposure windows and reasons for this global disparity remain unclear. This study aimed to investigate associations between perinatal and current animal exposure and childhood AS among 2598 preschoolers (aged 3–6) in Changsha, China. Data on AS and pet exposure were gathered via questionnaires, while children’s prenatal and current exposure to outdoor air pollutants (PM10, NO2) was estimated from monitoring stations. Multiple logistic regression models revealed an overall AS prevalence of 1.8%. Current animal or pet exposure was significantly associated with childhood AS (adjusted OR 2.40, 95% CI 1.12–4.29). Conversely, no significant association was found for perinatal exposure. Intriguingly, a stratified analysis showed that the association with current exposure was significant only in children exposed to low levels of outdoor PM10 (adj. OR 2.97, 95% CI 1.21–7.27) and NO2 (adj. OR 3.01, 95% CI 1.23–7.37). The study concludes that current exposure to pets significantly increases childhood AS risk. This effect is unexpectedly magnified in environments with low outdoor air pollution. This novel finding not only may explain the higher prevalence of pet allergies in developed countries but also suggests that as air quality improves alongside rising pet ownership, developing nations like China could face a significant future increase in pet sensitization, highlighting a critical emerging public health challenge.

1. Introduction

With the advancement of social technologies, individuals are experiencing increasing isolation and loneliness. Dogs have the ability to socialize flexibly and be sensitive to human behavior [1], and positive interactions such as sustained eye contact and hugging between humans and dogs cause oxytocin to spike in both, which is linked to positive emotions [2,3]. Keeping pets has a positive impact on mental health [4,5] through a series of mechanisms, including reducing stress [6,7], promoting social interaction [8,9], and providing emotional support [10]. In addition, psychological well-being improved with an increase in the number of pets owned, while life satisfaction rose with higher levels of perceived support from pets [11]. Pets are helpful as friends to children’s growth and development [12]. Therefore, the demand for the companionship of pets is constantly increasing. The proportion of pet owners ranges from about 19% in Greece to about 22% in South Korea and 70% in America [13,14,15,16]. The number of pets in Japan exceeds the number of children [17]. The increase in pet ownership led to an increase in asthma and allergic diseases over the past five years [18]. The prevalence of allergic sensitization (AS) to pets is growing and accompanies the increase in pet [19,20,21] ownership. AS to pets is considered one of the most important causes of severe asthma [22].
Sensitization to cat dander and other inhaled allergens is more frequent in preschool and school-age children [23]. The results of a recent study on the effect of early exposure (for example, perinatal and infantile exposure) to animal allergens on AS in childhood are complex and unclear [24,25,26]. The results of another study are contradictory [27]. Some studies have shown that animal ownership in early life can help prevent the risk of subsequent AS and asthma [28,29,30,31,32,33,34,35,36,37], some have reported that it has no effect [23,24,38,39,40], while others have suggested that it increases the risk of developing asthma [41,42]. However, more and more studies have shown that pet exposure [43], endotoxin [44,45,46,47] and air pollution [48,49,50] are all related to increased reports of allergies and asthma at some stage of life [51]. Many studies have shown that exposure to animals, and particularly to cats, can lead to a higher risk of AS in children [23,24,52,53]. In addition, research indicates that pet ownership is associated with increased asthma severity in children with atopic asthma, regardless of their pet sensitization status [54]. The key exposure window impacting AS to pets needs further study.
An estimated 10-30 percent of people show AS to pets in developed countries [55]. In most developing countries, the prevalence of AS to pets is much less than in developed countries [56]. The key reason of the difference is still unknown. A study has shown that keeping pets can reduce respiratory diseases and asthma in Chinese children caused by outdoor air pollution [51]. However, there are very few studies that investigate the effect of air pollution on the association between exposure to animals or pets and children’s AS.
The interplay between pet allergen exposure and air pollution is an area of growing interest. Epidemiologically, the varying air quality levels across regions with differing pet ownership rates might contribute to heterogeneous AS prevalences. Immunologically, air pollutants can act as adjuvants, potentially exacerbating immune responses to inhaled allergens like those from pets or increasing airway inflammation and permeability [57,58]. The odds ratios are crucial, especially in regions undergoing changes in both pet ownership and air quality.
The rising pet ownership, driven by socioeconomic shifts and changing lifestyles, has been paralleled by an increase in the global prevalence of allergic sensitization (AS) to pets [18,20,21,59]. A key paradox remains: the prevalence of pet-related AS is significantly higher in developed countries than in many developing nations, and the reasons for this disparity are poorly understood. One underexplored hypothesis is that ambient air pollution may modify the association between pet exposure and AS. Addressing this issue, this study draws on data from a large Chinese cohort and aims to answer two primary questions: (1) Is the critical window for pet-related AS development situated in the perinatal period or in the current period? (2) Could the effect of air pollution on pet–AS association help explain the observed global disparity in allergy prevalence?

2. Materials and Methods

2.1. Study Protocol and Questionnaire

This investigation drew upon data from a cross-sectional survey conducted in Changsha, China, between September 2011 and January 2012. This survey formed part of the national “China–Children–Homes–Health (CCHH)” study [60]. The study design received approval from the Ethics Committee of Central South University, and its methodology has been comprehensively detailed in prior publications [48]. Information collection was primarily facilitated by a standardized questionnaire, adapted from the International Study of Asthma and Allergies in Childhood (ISAAC) [20] and a Swedish questionnaire focused on building dampness and health (DBH) [19,61]. In total, 4,988 questionnaires were distributed to children attending 36 kindergartens (Figure 1). Following the exclusion of incomplete responses, a final dataset of 2598 valid questionnaires from children aged 3–6 years was incorporated into the analysis.

2.2. Exposure Windows

For outdoor air pollution, two primary exposure windows were defined: prenatal and current. The prenatal period encompassed the duration from the first month through the final month of pregnancy. The current period referred to the preceding 12 months or recent year. Similarly, exposure to animals or pets was categorized into perinatal and current periods, with the perinatal period signifying the child’s birth time.

2.3. Exposure to Animals or Pets

Perinatal and current exposure to animals or pets was ascertained through confirmed responses to two questionnaire items: “When the child was born, did you keep animals or pets in your residence?”; and “Currently, do you keep animals or pets in your residence?”

2.4. Exposure to Air Pollution

Three air pollutants were chosen for analysis: sulfur dioxide (SO2), nitrogen dioxide (NO2), and particulate matter with a diameter of ≤10 μm (PM10). SO2 served as an indicator of industrial-related air pollution (IRAP) [59,62,63], NO2 represented traffic-related air pollution (TRAP), and PM10 acted as a surrogate for complex pollutant mixtures [64]. The daily (24 h) average concentrations of these pollutants were procured from monitoring stations. Each child’s exposure to air pollution was then estimated using the inverse distance weighted (IDW) method, as described elsewhere [64]. The monthly average concentrations of PM10, SO2, and NO2 were utilized to compute prenatal exposure (spanning the entire pregnancy) and current exposure (covering the 12 months preceding questionnaire completion).

2.5. Health Outcome

The primary health outcome in this study was allergic sensitization (AS) to pets. This was identified by a positive response to the questionnaire item: “During the past 12 months, did your child have rhinitis-like and eye symptoms including sneezing, running nose, stuffy nose, eye pain, and tears after contact with pets?”

2.6. Confounding Covariates

Potential confounding variables, collected via the parent-administered questionnaire, included personal factors (child’s sex, age, birth season, breastfeeding status, antibiotic use, parental atopy, and house size) and indoor environmental factors [65]. The indoor environment-related factors comprised environmental tobacco smoke (ETS) exposure at home, presence of new indoor furniture, recent house redecoration, visible mold/damp stains, and winter window condensation [66,67,68,69,70,71]. Comprehensive details regarding these covariates are provided in Table S1.

2.7. Statistical Analysis

The associations between childhood AS to pets and both perinatal and current exposure to animals/pets, alongside the outdoor levels of air pollutants (PM10, SO2, and NO2), were assessed using multiple logistic regression models. The results are presented as odds ratios (ORs) with corresponding 95% confidence interval (95% CI). For childhood AS linked to pet exposure, ORs were derived from classification models, using non-exposure as the reference category. The relationship between childhood AS to pets and outdoor air pollutant exposure was investigated using continuous models. In these continuous models, OR (95% CI) values were calculated per interquartile range (IQR) increase for each pollutant. To explore the potential effect of air pollution, outdoor air pollutants (PM10, SO2, NO2) were stratified into low (<median)- and high (≥median)-exposure subgroups. This stratification was adopted for the initial exploratory analysis due to the limited number of AS cases, which could challenge the stability of continuous interaction models. While acknowledging that dichotomizing exposure variables may reduce statistical power and potentially obscure true dose–response relationships for an interaction, this approach provided a feasible starting point. The risk of AS to pets associated with current pet exposure was then evaluated within these established strata. A p-value less than 0.05 (p < 0.05) was deemed statistically significant. All statistical computations were performed using SPSS software (version 16.0, SPSS Inc., Chicago, IL, USA).

3. Results

Of the 2598 children, 48 (1.8%) had AS to pets in the last 12 months. Table 1 shows the prevalence of AS to pets stratified by covariates. We found that children with parental atopy (3.2%) had significantly higher prevalence than those without parental atopy (1.7%) (p < 0.05). New furniture was found to have a significant effect on AS to pets. We further observed a higher prevalence of AS to pets in boys (2.3%), children without breastfeeding (3.2%), and those living in a dwelling with mold/damp stains (2.6%) compared to girls (1.3%), children with breastfeeding (1.7%), and those living in a dwelling without mold/damp stains, although the difference did not reach statistical significance. However, no difference in the prevalence was observed among children stratified by all the other covariates, including age, birth season, antibiotics use, house size, ETS at home, house redecoration, and window condensation in winter.
Animal or pet ownership during the perinatal and current periods was reported by 9.2% and 14.2% of all families, respectively. Table 2 provides the association between exposure to animals or pets during the perinatal and current periods and childhood AS to pets. The ORs in the crude model was similar to that in the adjusted model. We found that only current exposure to animals or pets was significantly associated with childhood AS to pets, with adjusted OR (95% CI) = 2.40 (1.17–4.93). In contrast, no risk of AS to pets was observed due to perinatal exposure to animals or pets.
We did not find a significant risk of childhood AS to pets due to prenatal and current exposure to outdoor air pollutants including PM10, SO2, and NO2 (Table 3, personal exposure levels of the three air pollutants shown in Table S2). However, all ORs for pet-related AS associated with current exposure to outdoor air pollution were below 1.
A significant association between current exposure to animal or pets and AS to pets was detected in children with low exposure to outdoor air pollution (PM10 and NO2), respectively, with ORs (95% CI) = 2.97 (1.21–7.27) and 3.01 (1.23–7.37), compared to children with high exposure (Table 4).

4. Discussion

This study yields two principal findings. First, concerning the exposure window for pet-related allergic sensitization (AS) in preschool children, our data indicate that current exposure, rather than perinatal exposure, is the primary risk factor. Second, and most novel, this association appears to be significantly modified by ambient air pollution; the risk conferred by current pet exposure was only statistically significant in environments with lower concentrations of outdoor air pollutants.
Our finding on the critical exposure window aligns with a growing body of evidence. While some studies have reported no strong association between pet exposure in infancy and later sensitization [23,38,39], our results are consistent with research identifying ongoing animal contact as a significant risk factor for AS and respiratory symptoms at various life stages [51,72,73,74]. This distinction reinforces the hypothesis that for this age group, the allergenic risk stems more from concurrent exposure than from immune programming effects in early life.
The most important contribution of this study is the evidence for effect modification. The association between current pet exposure and AS was statistically significant only among children exposed to lower levels of PM10 (OR = 2.97, 95% CI: 1.21–7.27) and NO2 (OR = 3.01, 95% CI: 1.23–7.37). This observation is of considerable importance, as it offers a plausible explanation for a long-observed global paradox: the higher reported prevalence of pet allergies in developed countries, which generally have cleaner air, compared to many developing nations. To contextualize our setting, the air pollution level in Changsha (e.g., PM10: 85 μg/m3) is moderate on a national scale, making it a suitable environment to observe such modifying effects.
While our study was not designed to elucidate biological mechanisms, the observed interaction warrants speculation. Oxidative stress is a pathway implicated in many allergic disorders. Research has linked air pollutants like PAHs to allergic rhinitis via oxidative stress markers like 8-OHdG [75], and co-exposure to multiple pollutants has been shown to exacerbate symptoms by increasing markers such as malondialdehyde (MDA) [60]. It is conceivable that in low-pollution environments, the immune system’s response is more specifically directed toward pet allergens, whereas in high-pollution settings, a generalized, pollution-driven oxidative stress response dominates. Further research is needed to clarify this interplay.
Our study reveals a seemingly paradoxical finding: the allergenic risk associated with pet exposure is amplified in cleaner air environments. This observation is supported by multiple lines of immunological evidence. Early-life exposure to farm environments and pet animals protects against allergy/asthma primarily through microbiota-driven immunomodulation, involving innate immune activation (e.g., TLR pathways), microbial metabolites (e.g., butyrate-induced Tregs), and Th1/Treg bias, with the prenatal-infant period as the critical window for durable immune programming [76]. Some research has shown that diesel exhaust particles enhance allergen-induced acute immune responses by promoting Th2-type cytokines (IL-4/IL-5) and antibody production [77,78]. Our epidemiological data provide novel evidence for this concept, suggesting that in cleaner environments, the immune system may be less preoccupied by competing stimuli, thereby increasing its propensity to mount a specific allergic response to pet dander.
We hypothesize that in heavily polluted environments, the pronounced immunomodulatory effects of high-level air pollution may mask or supersede the more subtle allergenic effects of pets. This implication is particularly relevant to public health trends in China. The nation’s historically high levels of air pollution may have previously obscured the underlying risk of pet sensitization. Consequently, as China experiences two converging societal trends—rapidly rising pet ownership and steadily improving air quality—our findings suggest a significant, emerging public health challenge. The “clean air dividend” may be paradoxically accompanied by a substantial increase in pet sensitization, a phenomenon that warrants greater attention from public health authorities.
The findings of this study should be considered in light of several limitations. The primary strength is its basis in a large, multi-city cohort; however, the number of AS cases in our specific sample (n = 48) was small, which limits the statistical power for interaction analyses and means that these particular findings should be interpreted as exploratory. Second, the AS outcome was based on parental-reported symptoms rather than clinical validation, which could have led to misclassification. Third, our exposure assessments lacked granularity; air pollution was estimated from ambient monitors, and pet exposure was not characterized by type or intensity. The limit of the reliance on outdoor data is partly mitigated by the local subtropical climate in Changsha, where frequent window opening likely strengthens the indoor–outdoor air quality correlation. Fourth, our use of dichotomized pollution data for the interaction analysis, while necessary for model stability with limited cases, sacrificed information on dose–response relationships. Finally, the cross-sectional nature of the data on current exposure and AS prevents us from establishing causality.

5. Conclusions

Our study found that exposure to animals or pets during the current period was significantly associated with the prevalence of AS to pets in children, particularly those who lived in areas with low levels of outdoor air pollution. The effect of the exposure to low levels of air pollution on AS associated with exposure to animals or pets may contribute to the rapid increase in childhood animal allergic sensitization, especially in high-income countries. Our findings highlight that current pet exposure is a key risk for childhood AS, and this risk is amplified in cleaner air environments. Our findings signal an emerging public health challenge for nations undergoing simultaneous improvements in air quality and increases in pet ownership. This suggests that public health strategies may need to shift from focusing solely on pollution-related illnesses to preparing for a higher burden of allergic diseases, developing targeted interventions for at-risk populations in these progressively cleaner environments.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/atmos16070833/s1, Table S1: Descriptions of and questions about confounding covariates related to childhood allergic sensitization to pets in this study; Table S2: Descriptive statistics of exposure levels for children aged 3–6 years (n = 2598); Table S3: Summary of mean concentration of air pollutants during current period and prevalence of current animal ownership and of allergic sensitization to pets among children in 7 cities in China (n = 39,782).

Author Contributions

Writing—original draft preparation, Y.M. and Y.L.; methodology, Y.M.; software, Y.L.; validation, R.H. and Y.X.; formal analysis, Y.L.; investigation, R.H.; resources, Q.D.; data curation, R.H.; writing—review and editing, all authors; supervision, L.L. and Q.D. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Natural Science Foundation of China, grant number No. 41977369.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

We are particularly indebted to the children, their parents, and the kindergartens for their time and enthusiastic participation.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
ASAllergic sensitization
CCHHChina–Children–Homes–Health
ETSEnvironmental tobacco smoke
OROdds ratio
CIConfidence interval

References

  1. Ádám, M. The Science of a Friendship. Sci. Am. Mind 2015, 26, 37–45. [Google Scholar]
  2. Nagasawa, M.; Mitsui, S.; En, S.; Ohtani, N.; Ohta, M.; Sakuma, Y.; Onaka, T.; Mogi, K.; Kikusui, T.J.S. Oxytocin-gaze positive loop and the coevolution of human-dog bonds. Science 2015, 348, 333–336. [Google Scholar]
  3. Marshall-Pescini, S.; Schaebs, F.S.; Gaugg, A.; Meinert, A.; Deschner, T.; Range, F.J.A. The role of oxytocin in the dog–owner relationship. Animals 2019, 9, 792. [Google Scholar] [CrossRef]
  4. Goh, Y.X.; Tan, J.S.Q.; Syn, N.L.; Tan, B.S.W.; Low, J.Y.; Foo, Y.H.; Fung, W.; Hoong, B.Y.D.; Pang, J.; Phase IV CHP 2020 Group 8. Association between pet ownership and physical activity levels, atopic conditions, and mental health in Singapore: A propensity score-matched analysis. Sci. Rep. 2020, 10, 19898. [Google Scholar] [CrossRef]
  5. Reider, L.B.; Kim, E.; Mahaffey, E.; LoBue, V. The impact of household pets on children’s daily lives: Differences in parent–child conversations and implications for children’s emotional development. Dev. Psychol. 2023, 59, 2148–2161. [Google Scholar] [CrossRef] [PubMed]
  6. Ein, N.; Li, L.; Vickers, K. The effect of pet therapy on the physiological and subjective stress response: A meta-analysis. Stress Health 2018, 34, 477–489. [Google Scholar] [CrossRef]
  7. O’Haire, M. Companion animals and human health: Benefits, challenges, and the road ahead. J. Vet. Behav. 2010, 5, 226–234. [Google Scholar]
  8. Myers, O.E. No longer the lonely species: A post-mead perspective on animals and sociology. Int. J. Sociol. Soc. Policy 2003, 23, 46–68. [Google Scholar] [CrossRef]
  9. Power, E.R. Dogs and Practices of Community and Neighboring. Anthrozoös 2013, 26, 579–591. [Google Scholar] [CrossRef]
  10. Virués-Ortega, J.; Buela-Casal, G. Psychophysiological Effects of Human-Animal Interaction. J. Nerv. Ment. Dis. 2006, 194, 52–57. [Google Scholar] [CrossRef]
  11. Hardie, S.; Loc, M.D.; Howell, T.J. Social Support and Wellbeing in Cat and Dog Owners, and the Moderating Influence of Pet–Owner Relationship Quality. Anthrozoös 2023, 36, 891–907. [Google Scholar] [CrossRef]
  12. Jalongo, M.R. The World’s Children and Their Companion Animals: Developmental and Educational Significance of the Child/Pet Bond; Association for Childhood Education International: Washington, DC, USA, 2004. [Google Scholar]
  13. Burr, M.L.; Limb, E.S.; Andrae, S.; Barry, D.M.J.; Nagel, F. Childhood Asthma in Four Countries: A Comparative Survey. Int. J. Epidemiol. 1994, 23, 341–347. [Google Scholar] [CrossRef] [PubMed]
  14. McBride, D.; Keil, T.; Grabenhenrich, L.; Dubakiene, R.; Drasutiene, G.; Fiocchi, A.; Dahdah, L.; Sprikkelman, A.B.; Schoemaker, A.A.; Roberts, G.; et al. The EuroPrevall birth cohort study on food allergy: Baseline characteristics of 12,000 newborns and their families from nine European countries. Pediatr. Allergy Immunol. 2012, 23, 230–239. [Google Scholar] [CrossRef]
  15. Kim, C. Pooch Protection and Profit: South Korea to Overhaul Pet Sector [Internet]; Reuters: London, UK, 6 July 2016; Available online: http://www.reuters.com/article/us-southkoreaeconomy-pets-idUSKCN0ZN05V (accessed on 10 October 2017).
  16. Newman, A.; Smith, D.; Ghai, R.R.; Wallace, R.M.; Torchetti, M.K.; Loiacono, C.; Murrell, L.S.; Carpenter, A.; Moroff, S.; Rooney, J.A.J.M.; et al. First reported cases of SARS-CoV-2 infection in companion animals—New York, March–April 2020. Morb. Mortal. Wkly. Rep. 2020, 69, 710. [Google Scholar]
  17. Baba, Y. Pet Food Market in Japan; JA2021-0015; ATO: Osaka, Japan, 2021. [Google Scholar]
  18. Kalyoncu, A.; Demir, A.; Ozcakar, B.; Bozkurt, B.; Artvinli, M. Asthma and allergy in Turkish university students: Two cross-sectional surveys 5 years apart. Allergol. Immunopathol. 2001, 29, 264–271. [Google Scholar]
  19. Asher, M.I.; Montefort, S.; Björkstén, B.; Lai, C.K.; Strachan, D.P.; Weiland, S.K.; Williams, H.; Group, I.P.T.S. Worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: ISAAC Phases One and Three repeat multicountry cross-sectional surveys. Lancet 2006, 368, 733–743. [Google Scholar]
  20. Suh, M.; Kim, H.-H.; Sohn, M.H.; Kim, K.-E.; Kim, C.; Shin, D.C. Prevalence of allergic diseases among Korean school-age children: A nationwide cross-sectional questionnaire study. J. Korean Med. Sci. 2011, 26, 332–338. [Google Scholar]
  21. Salo, P.M.; Arbes Jr, S.J.; Jaramillo, R.; Calatroni, A.; Weir, C.H.; Sever, M.L.; Hoppin, J.A.; Rose, K.M.; Liu, A.H.; Gergen, P.J. Prevalence of allergic sensitization in the United States: Results from the National Health and Nutrition Examination Survey (NHANES) 2005–2006. J. Allergy Clin. Immunol. 2014, 134, 350–359. [Google Scholar]
  22. Lombardi, C.; Savi, E.; Ridolo, E.; Passalacqua, G.; Canonica, G.W. Is allergic sensitization relevant in severe asthma? Which allergens may be culprit? World Allergy Organ. J. 2017, 10, 2. [Google Scholar] [CrossRef]
  23. Chen, C.M.; Rzehak, P.; Zutavern, A.; Fahlbusch, B.; Bischof, W.; Herbarth, O.; Borte, M.; Lehmann, I.; Behrendt, H.; Kramer, U.; et al. Longitudinal study on cat allergen exposure and the development of allergy in young children. J. Allergy Clin. Immunol. 2007, 119, 1148–1155. [Google Scholar] [CrossRef]
  24. Chen, C.M.; Tischer, C.; Schnappinger, M.; Heinrich, J. The role of cats and dogs in asthma and allergy—A systematic review. Int. J. Hyg. Environ. Health 2010, 213, 1–31. [Google Scholar] [CrossRef]
  25. Lodge, C.J.; Allen, K.J.; Lowe, A.J.; Hill, D.J.; Hosking, C.S.; Abramson, M.J.; Dharmage, S.C.J.C.; Immunology, D. Perinatal cat and dog exposure and the risk of asthma and allergy in the urban environment: A systematic review of longitudinal studies. Clin. Dev. Immunol. 2012, 2012, 176484. [Google Scholar]
  26. Smallwood, J.; Ownby, D. Exposure to dog allergens and subsequent allergic sensitization: An updated review. Curr. Allergy Asthma Rep. 2012, 12, 424–428. [Google Scholar]
  27. Nilsson, O.B.; van Hage, M.; Gronlund, H. Mammalian-derived respiratory allergens–implications for diagnosis and therapy of individuals allergic to furry animals. Methods 2014, 66, 86–95. [Google Scholar] [CrossRef] [PubMed]
  28. Celedón, J.C.; Litonjua, A.A.; Ryan, L.; Platts-Mills, T.; Weiss, S.T.; Gold, D.R. Exposure to cat allergen, maternal history of asthma, and wheezing in first 5 years of life. Lancet 2002, 360, 781–782. [Google Scholar] [PubMed]
  29. Hesselmar, B.; Aberg, N.; Aberg, B.; Eriksson, B.; Björkstén, B.J.C. Does early exposure to cat or dog protect against later allergy development? Clin. Exp. Allergy J. Br. Soc. Allergy Clin. Immunol. 1999, 29, 611–617. [Google Scholar]
  30. Lau, S.; Illi, S.; Sommerfeld, C.; Niggemann, B.; Bergmann, R.; von Mutius, E.; Wahn, U.; the Multicentre Allergy Study Group. Early exposure to house-dust mite and cat allergens and development of childhood asthma: A cohort study. Lancet 2000, 356, 1392–1397. [Google Scholar]
  31. Lindfors, A.; van Hage-Hamsten, M.; Rietz, H.; Wickman, M.; Nordvall, S.L. Influence of interaction of environmental risk factors and sensitization in young asthmatic children. J. Allergy Clin. Immunol. 1999, 104, 755–762. [Google Scholar]
  32. Mandhane, P.J.; Sears, M.R.; Poulton, R.; Greene, J.M.; Lou, W.Y.W.; Taylor, D.R.; Hancox, R.J. Cats and dogs and the risk of atopy in childhood and adulthood. J. Allergy Clin. Immunol. 2009, 124, 745–750.e744. [Google Scholar] [CrossRef]
  33. Ownby, D.R.; Johnson, C.C.; Peterson, E.L.J.J. Exposure to dogs and cats in the first year of life and risk of allergic sensitization at 6 to 7 years of age. JAMA 2002, 288, 963–972. [Google Scholar]
  34. Remes, S.T.; Castro-Rodriguez, J.A.; Holberg, C.J.; Martinez, F.D.; Wright, A.L. Dog exposure in infancy decreases the subsequent risk of frequent wheeze but not of atopy. J. Allergy Clin. Immunol. 2001, 108, 509–515. [Google Scholar] [PubMed]
  35. de Moira, A.P.; Strandberg-Larsen, K.; Van Meel, E.; Mensink-Bout, R.; Popovic, M.; Cadman, T.; Yang, T.; Thorbjørnsrud Nader, J.; Foong, R.; Jankowska, A.; et al. Pet ownership and allergic sensitisation and asthma in childhood: Findings from the EU Child Cohort Network. Eur. Respir. J. 2020, 56, 435. [Google Scholar] [CrossRef]
  36. Rönmark, E.; Bunne, J.; Bjerg, A.; Perzanowski, M.; Winberg, A.; Andersson, M.; Platts-Mills, T.; Hedman, L. Prevalence and risk factors for allergic sensitization: 3 cross-sectional studies among schoolchildren from 1996 to 2017. J. Allergy Clin. Immunol. Glob. 2023, 2, 100150. [Google Scholar] [CrossRef]
  37. Toyokuni, K.; Yamamoto-Hanada, K.; Yang, L.; Hagino, K.; Harama, D.; Omori, M.; Matsumoto, Y.; Suzuki, D.; Umezawa, K.; Takada, K.; et al. Influence of household pet ownership and filaggrin loss-of-function mutations on eczema prevalence in children: A birth cohort study. Allergol. Int. 2024, 73, 422–427. [Google Scholar] [CrossRef]
  38. Wegienka, G.; Johnson, C.C.; Havstad, S.; Ownby, D.R.; Zoratti, E.M. Indoor pet exposure and the outcomes of total IgE and sensitization at age 18 years. J. Allergy Clin. Immunol. 2010, 126, 274–279.e275. [Google Scholar] [CrossRef]
  39. Lodge, C.J.; Lowe, A.J.; Gurrin, L.C.; Matheson, M.; Balloch, A.; Axelrad, C.; Hill, D.J.; Hosking, C.S.; Rodrigues, S.; Svanes, C.J.C.; et al. Pets at birth do not increase allergic disease in at-risk children. Clin. Exp. Allergy 2012, 42, 1377–1385. [Google Scholar] [PubMed]
  40. Wypych-Ślusarska, A.; Krupa-Kotara, K.; Oleksiuk, K.; Głogowska-Ligus, J.; Słowiński, J. Respiratory Status in Children and Exposure to Animal Allergens—The Problem of Reverse Causality in Cross-Sectional Studies. Children 2024, 11, 941. [Google Scholar]
  41. Bertelsen, R.J.; Lødrup Carlsen, K.C.; Carlsen, K.H.; Granum, B.; Doekes, G.; Håland, G.; Mowinckel, P.; Løvik, M. Childhood asthma and early life exposure to indoor allergens, endotoxin and β(1,3)-glucans. Clin. Exp. Allergy 2010, 40, 307–316. [Google Scholar] [CrossRef] [PubMed]
  42. Downes, M.J.; Roy, A.; McGinn, T.G.; Wisnivesky, J.P. Factors Associated with Furry Pet Ownership Among Patients with Asthma. J. Asthma 2010, 47, 742–749. [Google Scholar] [CrossRef]
  43. Ownby, D.; Johnson, C.C. Recent Understandings of Pet Allergies. F1000Res 2016, 5, 108. [Google Scholar] [CrossRef]
  44. Johnston, R. Clearing the Air: Asthma and Indoor Air Exposures; National Academies Press: Washington, DC, USA, 2000. [Google Scholar]
  45. Zhu, Z.; Oh, S.Y.; Zheng, T.; Kim, Y.-K. Immunomodulating effects of endotoxin in mouse models of allergic asthma. Clin. Exp. Allergy 2010, 40, 536–546. [Google Scholar] [CrossRef] [PubMed]
  46. Chinn, S.; Heinrich, J.; Anto, J.M.; Janson, C.; Norback, D.; Olivieri, M.; Svanes, C.; Sunyer, J.; Verlato, G.; Wjst, M.; et al. Bronchial responsiveness in atopic adults increases with EXDOsure to cat alleraen. Am. J. Respir. Crit. Care Med. 2007, 176, 20–26. [Google Scholar] [CrossRef]
  47. Shamsollahi, H.R.; Ghoochani, M.; Jaafari, J.; Moosavi, A.; Sillanpää, M.; Alimohammadi, M. Environmental exposure to endotoxin and its health outcomes: A systematic review. Ecotoxicol. Environ. Saf. 2019, 174, 236–244. [Google Scholar] [PubMed]
  48. Deng, Q.; Lu, C.; Li, Y.; Sundell, J.; Norbäck, D. Exposure to outdoor air pollution during trimesters of pregnancy and childhood asthma, allergic rhinitis, and eczema. Environ. Res. 2016, 150, 119–127. [Google Scholar] [CrossRef]
  49. Shakerkhatibi, M.; Benis, K.Z.; Asghari-Jafarabadi, M.; Sadeghi-Bazarghani, H.; Allahverdipour, H.; Oskouei, D.S.; Fatehifar, E.; Farajzadeh, M.; Yadeghari, A.; Ansarin, K.; et al. Air pollution-related asthma profiles among children/adolescents: A multi-group latent class analysis. Ecotoxicol. Environ. Saf. 2021, 219, 112344. [Google Scholar] [CrossRef] [PubMed]
  50. Isa, K.N.M.; Jalaludin, J.; Elias, S.M.; Than, L.T.L.; Jabbar, M.A.; Saudi, A.S.M.; Norbäck, D.; Hashim, J.H.; Hashim, Z. Metagenomic characterization of indoor dust fungal associated with allergy and lung inflammation among school children. Ecotoxicol. Environ. Saf. 2021, 221, 112430. [Google Scholar]
  51. Qian, Z.; Dong, G.-H.; Ren, W.-H.; Simckes, M.; Wang, J.; Zelicoff, A.; Trevathan, E. Effect of pet ownership on respiratory responses to air pollution in Chinese children: The Seven Northeastern Cities (SNEC) study. Atmos. Environ. 2014, 87, 47–52. [Google Scholar] [CrossRef]
  52. Hölscher, B.; Frye, C.; Wichmann, H.E.; Heinrich, J. Exposure to pets and allergies in children. Pediatr. Allergy Immunol. 2002, 13, 334–341. [Google Scholar]
  53. Roost, H.-P.; Künzli, N.; Schindler, C.; Jarvis, D.; Chinn, S.; Perruchoud, A.P.; Ackermann-Liebrich, U.; Burney, P.; Wüthrich, B. Role of current and childhood exposure to cat and atopic sensitization. J. Allergy Clin. Immunol. 1999, 104, 941–947. [Google Scholar]
  54. Song, K.-B.; Kim, J.-H.; Choi, E.J.; Lee, S.W.; Kim, J.T.; Lim, D.H.; Kim, W.K.; Song, D.J.; Yoo, Y.; Suh, D.I.; et al. Pet Ownership Increases the Exhaled Nitric Oxide and Asthma Severity in Children With Atopic Asthma. Allergy Asthma Immunol. Res. 2025, 17, 394–404. [Google Scholar]
  55. El Sharif, N.; Douwes, J.; Hoet, P.; Doekes, G.; Nemery, B.J.A. Concentrations of domestic mite and pet allergens and endotoxin in Palestine. Allergy 2004, 59, 623–631. [Google Scholar]
  56. Huang, Z.; Feng, W.; Wei, W.; Yang, B.; Wang, L. Prevalence of food-allergen and aeroallergen sensitization among people in Sichuan, Western China: An 8-year observational study. J. Clin. Lab. Anal. 2019, 33, e22723. [Google Scholar]
  57. Hassen, H.Y.; Govarts, E.; Remy, S.; Cox, B.; Iszatt, N.; Portengen, L.; Covaci, A.; Schoeters, G.; Den Hond, E.; Henauw, S.; et al. Association of environmental pollutants with asthma and allergy, and the mediating role of oxidative stress and immune markers in adolescents. Environ. Res. 2025, 265, 120445. [Google Scholar] [CrossRef]
  58. Li, J.; Wu, H.; Xing, W.; Li, X.; Han, Z.; Ji, R.; Deng, Z.; Jung, M.; Sun, S.; Chung, B.I.; et al. Air pollution mixture associated with oxidative stress exacerbation and symptoms deterioration in allergic rhinitis patients: Evidence from a panel study. Sci. Total Environ. 2024, 930, 172688. [Google Scholar] [CrossRef]
  59. Hu, Y.; Zhao, B. Relationship between indoor and outdoor NO2: A review. Build. Environ. 2020, 180, 106909. [Google Scholar]
  60. Zhang, Y.; Li, B.; Huang, C.; Yang, X.; Qian, H.; Deng, Q.; Zhao, Z.; Li, A.; Zhao, J.; Zhang, X.; et al. Ten cities cross-sectional questionnaire survey of children asthma and other allergies in China. Chin. Sci. Bull. 2013, 58, 4182–4189. [Google Scholar]
  61. Bornehag, C.-G.; Sundell, J.; Sigsgaard, T.J.I.A. Dampness in buildings and health (DBH): Report from an ongoing epidemiological investigation on the association between indoor environmental factors and health effects among children in Sweden. Indoor Air 2004, 14, 59–66. [Google Scholar]
  62. Lu, C.; Liu, Z.; Liao, H.; Yang, W.; Liu, Q.; Li, Q.; Deng, Q. Interaction of exposure to outdoor air pollution and temperature during pregnancy on childhood asthma: Identifying specific windows of susceptibility. Build. Environ. 2022, 225, 109676. [Google Scholar]
  63. Westgate, S.; Ng, N.L. Using in-situ CO2, PM1, PM2.5, and PM10 measurements to assess air change rates and indoor aerosol dynamics. Build. Environ. 2022, 224, 109559. [Google Scholar]
  64. Deng, Q.; Lu, C.; Norbäck, D.; Bornehag, C.-G.; Zhang, Y.; Liu, W.; Yuan, H.; Sundell, J. Early life exposure to ambient air pollution and childhood asthma in China. Environ. Res. 2015, 143, 83–92. [Google Scholar]
  65. Zhang, X.; Lu, C.; Li, Y.; Norbäck, D.; Murthy, P.; Sram, R.J.; Deng, Q. Early-life exposure to air pollution associated with food allergy in children: Implications for ‘one allergy’concept. Environ. Res. 2023, 216, 114713. [Google Scholar]
  66. Norbäck, D.; Lu, C.; Wang, J.; Zhang, Y.; Li, B.; Zhao, Z.; Huang, C.; Zhang, X.; Qian, H.; Sun, Y. Asthma and rhinitis among Chinese children—Indoor and outdoor air pollution and indicators of socioeconomic status (SES). Environ. Int. 2018, 115, 1–8. [Google Scholar]
  67. Geng, M.; Tang, Y.; Liu, K.; Huang, K.; Yan, S.; Ding, P.; Zhang, J.; Wang, B.; Wang, S.; Li, S.; et al. Prenatal low-dose antibiotic exposure and children allergic diseases at 4 years of age: A prospective birth cohort study. Ecotoxicol. Environ. Saf. 2021, 225, 112736. [Google Scholar] [CrossRef]
  68. Lu, C.; Miao, Y.; Zeng, J.; Jiang, W.; Shen, Y.-M.; Deng, Q. Prenatal exposure to ambient temperature variation increases the risk of common cold in children. Ecotoxicol. Environ. Saf. 2018, 154, 221–227. [Google Scholar]
  69. Cai, J.; Li, B.; Yu, W.; Wang, L.; Yao, Y.; Wang, Y. Damp indicators in different areas of residence in different periods are strongly associated with childhood asthma and wheeze. Build. Environ. 2020, 182, 107131. [Google Scholar]
  70. Lu, C.; Liao, H.; Liu, Z.; Yang, W.; Liu, Q.; Li, Q. Association between early life exposure to indoor environmental factors and childhood asthma. Build. Environ. 2022, 226, 109740. [Google Scholar]
  71. Zhang, X.; Li, X.; Wang, Z.; Deng, G.; Wang, Z. Exposure level and influential factors of HCHO, BTX and TVOC from the interior redecoration of residences. Build. Environ. 2020, 168, 106494. [Google Scholar]
  72. Konradsen, J.R.; Fujisawa, T.; van Hage, M.; Hedlin, G.; Hilger, C.; Kleine-Tebbe, J.; Matsui, E.C.; Roberts, G.; Ronmark, E.; Platts-Mills, T.A. Allergy to furry animals: New insights, diagnostic approaches, and challenges. J. Allergy Clin. Immunol. 2015, 135, 616–625. [Google Scholar] [CrossRef]
  73. Chen, C.-M.; Gehring, U.; Wickman, M.; Hoek, G.; Giovannangelo, M.; Nordling, E.; Wijga, A.; de Jongste, J.; Pershagen, G.; Almqvist, C.; et al. Domestic cat allergen and allergic sensitisation in young children. Int. J. Hyg. Environ. Health 2008, 211, 337–344. [Google Scholar] [CrossRef]
  74. Won, J.Y.; Kwon, J.-W.; Hong, S.-N.; Lee, W.H. Age differences in pet sensitization by pet ownership. Clin. Exp. Otorhinolaryngol. 2021, 14, 210–216. [Google Scholar]
  75. Cong, W.; Elsheikha, H.M.; Zhou, N.; Peng, P.; Qin, S.-Y.; Meng, Q.-F.; Qian, A.-D. Prevalence of antibodies against Toxoplasma gondii in pets and their owners in Shandong province, Eastern China. BMC Infect. Dis. 2018, 18, 430. [Google Scholar]
  76. Kääriö, H. The Allergy and Asthma Protective Effects of Farm Environment and Pet Animals: The Role of Immunomodulation. Ph.D. Thesis, Itä-Suomen Yliopisto, Joensuu, Finland, 2015. [Google Scholar]
  77. Mazzarella, G.; Esposito, V.; Bianco, A.; Ferraraccio, F.; Prati, M.V.; Lucariello, A.; Manente, L.; Mezzogiorno, A.; De Luca, A. Inflammatory effects on human lung epithelial cells after exposure to diesel exhaust micron sub particles (PM1.0) and pollen allergens. Environ. Pollut. 2012, 161, 64–69. [Google Scholar] [CrossRef]
  78. Takano, H.; Ichinose, T.; Miyabara, Y.; Yoshikawa, T.; Sagai, M. Diesel exhaust particles enhance airway responsiveness following allergen exposure in mice. Immunopharmacol. Immunotoxicol. 1998, 20, 329–336. [Google Scholar]
Atmosphere 16 00833 g001
Figure 1. Distribution of 36 kindergartens and seven air pollution monitoring stations in Changsha.
Figure 1. Distribution of 36 kindergartens and seven air pollution monitoring stations in Changsha.
Atmosphere 16 00833 g001
Table 1. Covariates, demographic information, and prevalence of allergic sensitization to pets among children 3–6 years old (n = 2598).
Table 1. Covariates, demographic information, and prevalence of allergic sensitization to pets among children 3–6 years old (n = 2598).
n (Case)/N (Number)Prevalence (%)p-Value
Total48/25981.8—
Sex
Boys32/13992.30.071
Girls16/11991.3
Age (years)
310/6651.50.182
414/9521.5
522/8152.7
62/1661.2
Birth season
Warm (May–September)21/11521.80.928
Cold (October–April)27/14461.9
Breastfeeding
No7/2223.20.124
Yes41/23761.7
Antibiotics use
No7/4321.60.650
Yes41/21151.9
Parental atopy
No3722141.70.046
Yes11/3403.2
House size (m2)
≤7519/8362.3 0.306
>7529/17321.7
Environmental tobacco smoke (ETS) at home
No16/8641.90.997
Yes32/17341.8
Indoor new furniture
No16/12481.3 0.036
Yes28/11562.4
House redecoration
No26/16891.5 0.356
Yes13/6202.1
Visible mold/damp stains at home
No32/19851.6 0.101
Yes16/6062.6
Window condensation in winter
No18/11751.5 0.217
Yes30/13692.2
The p-values < 0.05 are in bold.
Table 2. Association between perinatal and current animal or pet ownership and allergic sensitization to pets in children (n = 2598).
Table 2. Association between perinatal and current animal or pet ownership and allergic sensitization to pets in children (n = 2598).
n with AS/total N(%)Crude OR (95% CI)Adjusted OR (95% CI) #
Perinatal animal or pet ownership
No (Ref = no pet exposure)44/2341(1.9)11
Yes4/238(1.7)0.89 (0.32–2.51)1.09 (0.38–3.15)
Current animal or pet ownership
No (Ref = no pet exposure)36/2216(1.6)11
Yes12/369(3.3)2.02 (1.04–3.93) *2.40 (1.17–4.93) *
# Models were adjusted for all the covariates in Table 1. * p ≤ 0.05.
Table 3. Associations between prenatal and current exposure to outdoor air pollution and allergic sensitization to pets in children (n = 2598).
Table 3. Associations between prenatal and current exposure to outdoor air pollution and allergic sensitization to pets in children (n = 2598).
Crude OR (95% CI)Adjusted OR (95% CI) #
Outdoor air pollution
Prenatal
PM101.09 (0.80–1.48)0.84 (0.50–1.42)
SO21.12 (0.77–1.65)0.92 (0.55–1.53)
NO20.74 (0.47–1.16)0.62 (0.33–1.14)
Current
PM100.83 (0.46–1.48)0.64 (0.32–1.28)
SO20.99 (0.61–1.61)0.90 (0.52–1.57)
NO20.94 (0.50–1.75)0.74 (0.36–1.55)
OR (95% CI) was estimated for an IQR increase in PM10, SO2, and NO2. # Models were adjusted for all the covariates in Table 1.
Table 4. Associations between current animal or pet ownership and allergic sensitization to pets in children stratified by low and high levels of current exposure to outdoor air pollution (n = 2598).
Table 4. Associations between current animal or pet ownership and allergic sensitization to pets in children stratified by low and high levels of current exposure to outdoor air pollution (n = 2598).
Exposure LevelNumberOR (95% CI)
Outdoor air pollution
PM10Low12772.97 (1.21–7.27) *
High(13211.60 (0.43–5.91)
SO2Low12882.22 (0.84–5.89)
High13102.80 (0.93–8.46)
NO2Low12833.01 (1.23–7.37) *
High13151.59 (0.43–5.86)
Exposure levels were divided into low (<median) and high (≥median) categories. (For detailed exposure levels please refer to Table S2). OR (95% CI) was adjusted for all the covariates in Table 1. * p ≤ 0.05.
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Miao, Y.; Liu, Y.; Huang, R.; Xue, Y.; Liu, L.; Deng, Q. Children’s Allergic Sensitization to Pets: The Role of Air Pollution. Atmosphere 2025, 16, 833. https://doi.org/10.3390/atmos16070833

AMA Style

Miao Y, Liu Y, Huang R, Xue Y, Liu L, Deng Q. Children’s Allergic Sensitization to Pets: The Role of Air Pollution. Atmosphere. 2025; 16(7):833. https://doi.org/10.3390/atmos16070833

Chicago/Turabian Style

Miao, Yufeng, Yingjie Liu, Ruixue Huang, Yuan Xue, Le Liu, and Qihong Deng. 2025. "Children’s Allergic Sensitization to Pets: The Role of Air Pollution" Atmosphere 16, no. 7: 833. https://doi.org/10.3390/atmos16070833

APA Style

Miao, Y., Liu, Y., Huang, R., Xue, Y., Liu, L., & Deng, Q. (2025). Children’s Allergic Sensitization to Pets: The Role of Air Pollution. Atmosphere, 16(7), 833. https://doi.org/10.3390/atmos16070833

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